O-(substituted allylic) dithiophosphonate insecticides

ABSTRACT

Compounds having the formula ##STR1## in which R 1  is methyl or ethyl; R 2  is C 1  -C 6  alkyl; R 3  is hydrogen, halogen or methyl; and R 4  is hydrogen, methyl or phenyl; or R 3  and R 4  taken together form a tetramethylene chain; provided that R 3  and R 4  are not both hydrogen, are insecticides and/or nematicides.

This invention relates to a series of dithiophosphonate insecticideshaving the formula ##STR2## in which R₁ is methyl or ethyl; R₂ is C₁ -C₆alkyl; R₃ is hydrogen, halogen or methyl; and R₄ is hydrogen, methyl orphenyl; or R₃ and R₄ taken together form a tetramethylene chain;provided that R₃ and R₄ are not both hydrogen, together withinsecticidal compositions containing such compounds, and methods fortheir use in controlling insects.

The term "alkyl" refers to straight or branched chain saturatedaliphatic moieties, such as methyl, ethyl, n-propyl, isopropyl,sec.-butyl, tert.-butyl and the like. The term "halogen" includesfluoro, chloro, bromo and iodo.

When R₃ and R₄ are combined to form a tetramethylene chain, thecompounds are O-cyclohexenylmethyl dithiophosphonates.

The term "insects" as used herein refers to the broad and commonlyunderstood usage rather than to those creatures which in the strictbiological sense are classified as insects, and includes, in addition tothose belonging to the class Insecta, some classes of acarids such asspiders, mites, ticks, and the like, particularly mites.

The compounds of this invention have demonstrated activity against anumber of insect species, and show particularly good activity againstsoil-borne insects. Some compounds also demonstrate nematicidalactivity.

The compounds of the present invention were prepared by two methodsdesignated methods (A) and (B) below.

METHOD (A)

In this procedure the appropriate S-alkyl phosphonodithioic halide(preferably chloride) is reacted with a suitable allylic alkoxideaccording to the equation: ##STR3## in which R₁ -R₄ are as defined aboveand X stands for halogen, preferably chlorine or bromine, and M standsfor an alkali metal, preferably sodium or potassium.

Reaction (1) is generally carried out at a temperature of from about 0°to about 70° C., preferably from about 0° to about 25° C., in an organicsolvent. Suitable solvents include aromatic hydrocarbons such as benzeneor toluene, and ethers such as diethylether, 1,2-dimethoxyethane, ortetrahydrofuran (the preferred solvent). The allylic alkoxide isproduced by reaction of an allylic alcohol with analkalimetal-containing base. Suitable bases include sodium and potassiumhydride, with sodium hydride preferred. The desired product can berecovered and purified by evaporation of solvent and chromatography.

The S-alkyl phosphonodithioic halide may be prepared by any conventionalmeans, such as by reaction of an alkyl mercaptan with analkylphosphonothioic dihalide as described in U.S. Pat. No. 4,258,038 orby reaction of an alkyl mercaptan with an alkyl dihalophosphine,followed by reaction with hydrogen sulfide, as described in Akamsin, et.al., Chemical Abstracts, Vol. 68, No. 29783x (1968).

The process of this invention is preferable for S-tertiary and secondaryalkyl compounds, but less so for other S-alkyl phosphonodithioichalides; low yields or mixtures of difficultly separable products mayresult.

METHOD (B)

This procedure involves the sequential reaction of the appropriate alkylthionophosphine sulfide, first with an allylic alcohol in the presenceof a base, and then with an alkyl halide: ##STR4## in which R₁ -R₄ areas defined above and Y is a halogen, preferably bromine or iodine.

This method can be used for preparation of all compounds of thisinvention except those in which R₂ is a tertiary alkyl group.

The starting material sulfides for reaction (2) may be obtained by theprocedure described in P. E. Newallis, et al., Journal of OrganicChemistry, 1962, Vol. 27, p. 3829.

The process is generally carried out at a temperature of from about 0°to about 110° C., preferably from about 0° to about 70° C., in anorganic solvent. Suitable solvents include aromatic hydrocarbons such asbenzene or toluene, ethers such as diethyl ether, 1,2-dimethoxyethane,or tetrahydrofuran (preferred) and nitriles such as acetonitrile.Suitable bases are tertiary amines such as triethylamine (preferred),dimethylaniline, diethylaniline and pyridine. Inorganic bases such assodium or potassium carbonate may be used. The product may be recoveredby evaporation of the solvent and purified by chromatography ordistillation.

The following represent examples of the preparation of compounds of thisinvention.

EXAMPLE 1 Preparation ofO-(2-Buten-1-yl)S-t-butylethylphosphonodithioate (Compound 3 herein,Method A)

To a slurry of 0.36 grams (g) (0.0152 mole) of oil-free sodium hydridein 15 milliliters (ml) of tetrahydrofuran under nitrogen and at roomtemperature was added 1.18 ml (1.00 g, 0.0138 mole) of 2-buten-1-ol roomtemperature was added 1.18 ml (1.00 g, 0.0138 mole) of 2-buten-1-oldropwise. After stirring for 45 minutes, the mixture was cooled to 0°and a solution of 3.0 g (0.0138 mole) of S-t-butylethylphosphonodithioic chloride in 5 ml of tetrahydrofuran was addeddropwise and the mixture stirred for 3 hours at room temperature. Themixture was quenched with 10 ml of water and extracted with ether (3×10ml). The ethereal layers were combined and washed with 10 ml of waterand 20 ml of saturated sodium chloride, dried with magnesium sulfate,and evaporated to 3.1 g of an oil. Purification with a preparative,centrifugally-accelerated, thin-layer chromatograph (4 mm thick silicagel with 98:2 hexane-acetone as eluent) afforded 2.13 g (61%) of thetitle compound, a clear, mobile oil. The structure was confirmed bynuclear magnetic resonance, infrared and mass spectroscopy.

EXAMPLE 2 Preparation of O-(2-Methyl-2-propen-1-yl S-n-propylmethylphosphonodithioate (Compound 8 herein, Method B)

To a slurry of 2.08 g (0.0095 mole) of methylthionophosphine sulfide in20 ml of tetrahydrofuran under nitrogen and at room temperature wasadded 1.6 ml (1.36 g, 0.019 mole) of 2-methyl-2-propen-1-ol. After thesulfide had completely dissolved, 2.9 ml (2.03 g, 0.0201 mole) oftriethylamine was added, followed by the addition of 1.83 mg (2.47 g,0.0201 mole) of 1-bromopropane. The mixture was refluxed for 3 hours.The mixture was quenched with 10 ml of water and extracted with ether(3×10 ml). The ethereal layers were combined and washed with 10 ml ofwater and 10 ml of saturated sodium chloride, dried with magnesiumsulfate, and evaporated to 4.06 g of an oil. Purification with apreparative, centrifugally-accelerated, thin-layer chromatograph (4 mmthick silica gel with 98:2 hexane-acetone as eluent) afforded 2.68 g(63%) of the title compound, a clear, mobile oil. The structure wasconfirmed by nuclear magnetic resonance, infrared, and massspectroscopy.

The following Table I depicts representative compounds of thisinvention, which may be prepared by the processes previously described.Structures of these compounds were confirmed by analysis as above.

                  TABLE I                                                         ______________________________________                                         ##STR5##                                                                     Compound                                 Method of                            Number  R.sub.1                                                                              R.sub.2  R.sub.3                                                                            R.sub.4                                                                             n.sub.D.sup.30                                                                      Preparation                          ______________________________________                                        1       C.sub.2 H.sub.5                                                                      t-C.sub.4 H.sub.9                                                                      CH.sub.3                                                                           H     1.5298                                                                              A                                    2       CH.sub.3                                                                             sec-C.sub.4 H.sub.9                                                                    CH.sub.3                                                                           H     1.5253                                                                              A                                    3       C.sub.2 H.sub.5                                                                      t-C.sub.4 H.sub.9                                                                      H    CH.sub.3                                                                            1.5324                                                                              A                                    4       CH.sub.3                                                                             sec-C.sub.4 H.sub.9                                                                    H    CH.sub.3                                                                            1.5289                                                                              A                                    5       CH.sub.3                                                                             t-C.sub.4 H.sub.9                                                                      CH.sub.3                                                                           H     1.5311                                                                              A                                    6       CH.sub.3                                                                             CH.sub.3 CH.sub.3                                                                           H     1.5455                                                                              B                                    7       CH.sub.3                                                                             n-C.sub.3 H.sub.7                                                                      H    CH.sub.3                                                                            1.5332                                                                              B                                    8       CH.sub.3                                                                             n-C.sub.3 H.sub.7                                                                      CH.sub.3                                                                           H     1.5303                                                                              B                                    9       CH.sub.3                                                                             t-C.sub.4 H.sub.9                                                                      H    C.sub.6 H.sub.5                                                                     1.5919                                                                              A                                    10      CH.sub.3                                                                             t-C.sub.4 H.sub.9                                                                      CH.sub.3                                                                           CH.sub.3                                                                            1.5355                                                                              A                                    11      CH.sub.3                                                                             sec-C.sub.4 H.sub.9                                                                    CH.sub.3                                                                           CH.sub. 3                                                                           1.5279                                                                              A                                    12      CH.sub.3                                                                             t-C.sub.4 H.sub.9                                                                      (CH.sub.2).sub.4                                                                       1.5477                                                                              A                                      ______________________________________                                    

Insecticidal Evaluation Tests

The compounds in Table I above were tested for insecticidal activityusing the following testing procedures. LD-50 values, based on theresults of these tests, and/or calculated according to dosage-mortalitycurves, are expressed in Table II.

Housefly [Musca domestica]:

(a.) Contact: Test compounds were diluted in acetone and aliquotspipetted onto the bottom of aluminum dishes. To insure even spreading ofthe chemical on the bottom of the dishes, 1 ml of acetone containing0.01% peanut oil was also added to each dish. After all solvents hadevaporated, the dishes were placed in circular cardboard cagescontaining 25 female houseflies, 1-2 days old. The cages were covered onthe bottom with cellophane and on the top with tulle netting, and eachcontained a sugar-water saturated cotton plug for maintenance of theflies. Mortality was recorded after 48 hours. Test levels ranged from100 μg/25 female houseflies downward. The LD-50 values are expressedbelow in Table II under the heading "HF-C", in terms of μg of the testcompound per 25 female flies.

(b.) Fumigant: Test compounds were diluted in acetone and aliquotspipetted onto 55 millimeter (mm) filter paper discs in the bottom ofaluminum dishes. Immediately after the acetone had completely evaporatedthe dishes were placed in circular cardboard cages (volume--285 ml)containing 25 female houseflies. The cages were sealed on both ends withcellophane and each contained a sugar-water saturated cotton plug formaintenance of the flies. A piece of netting was placed over thealuminum dish in the cage in such a way that the flies were unable tocome into direct contact with the chemically treated filter paper.Mortality was recorded after 48 hours. Test levels ranged from 100 μg/25female houseflies downward. The LD-50 values are expressed in thefollowing Table II under the heading "HF-F", in terms of μg of the testcompound per 25 female houseflies per 285 ml volume of the testcontainer.

Black Bean Aphid [Aphis fabae (Scop.)]:

Nasturtium plants (Tropaeolum sp.) approximately 5 cm tall, weretransplanted into sandy loam soil in small cups and infested with 25-50black bean aphids of mixed ages. Twenty-four hours later they weresprayed to the point of runoff with 50--50 acetone-water solutions ofthe test compounds. Treated plants were held in the greenhouse andmortality was recorded after 48 hours. Test concentrations ranged from0.05% downward. The LD-50 values are expressed below in Table II underthe heading "BA-C" in terms of percent of the test compound in thesprayed solution.

Tobacco Budworm [Heliothis virescens (Fabricius)]:

(a) Contact: Test compounds were diluted in a 50--50 acetone-watersolution. Cotton (Gossypium sp.) cotyledons were immersed in the testsolutions for 2-3 seconds and placed on a wire screen to dry. The driedleaves were placed in petri dishes containing a moistened piece offilter paper and infested with 5 second-instar tobacco budworm larvae.The dishes were placed in a high humidity chamber for 5 days, andpercent mortality of the larvae recorded. Test concentrations rangedfrom 0.1% downward. The LD-50 values are expressed below in Table IIunder the heading "TBW-C" in terms of percent of the test compound inthe solution.

(b). Eggs: Paper towel patches of 2-day old eggs of the tobacco budwormwere dipped in acetone solutions of the test compounds and placed inpetri dishes containing a portion of larval rearing medium. Treated eggswere maintained at 78° F. and mortality was recorded after all controleggs had hatched and the young larvae were feeding on the media. Testconcentrations ranged from 0.1% downward. The LD-50 values are expressedbelow in Table II under the heading "TBW-E" in terms of percent of thetest compound in the solution.

Beet Armyworm (Spodoptera exigua):

Test compounds were diluted in a 50--50 acetone-water solution. Youngleaves of sugar beets (Beta vulgaris) were immersed in the testsolutions for 2-3 seconds and placed on a wire screen to dry. The driedleaves were placed in petri dishes containing a moistened filter paperand infested with five second-instar beet armyworm larvae. The disheswere placed in a high humidity chamber. Mortality of the larvae wasrecorded five days later. Test concentrations ranged from 0.1% downward.The LD-50 values are expressed below in Table II under the heading "BAW"in terms of percent of the test compound in solution.

Cabbage Looper [Trichoplusia ni (Hubner)]:

Test compounds were diluted in a 50--50 acetone-water solution.Cotyledons of hyzini squash (Calabacita abobrinha), approximately 1×1.5inches, were immersed in the test solutions for 2-3 seconds and placedon a wire screen to dry. The dried leaves were placed in petri dishescontaining a moistened piece of filter paper and infested with 5second-instar cabbage looper larvae. The dishes were placed in a highhumidity chamber. Mortality of the larvae was recorded 5 days later.Test concentrations ranged from 0.1% downward. The LD-50 values areexpressed below in Table III under the heading "CL" in terms of percentof the test compound in this solution.

Western Spotted Cucumber Beetle Larvae [Diabrotica undecimpunctataundecimpunctata (Mannherheim)]:

Ten grams of moist potting soil was placed in a plastic cup. Testcompounds were dissolved in acetone or an other appropriate solvent. A0.05 ml aliquot of the test sample, diluted to the desiredconcentration, was added to the soil. The cup was capped and the soilwas mixed on a vortex mixer for approximately 15 seconds. An indentationwas made on the surface of the soil and approximately 50 Diabrotica eggswere added. The eggs were covered with soil and maintained at roomtemperature (approximately 70° F. or 21° C.). Four days later a sectionof Romaine lettuce (Latuca sativa) leaf was placed in the treated cups.One week later the cups were examined for live larvae. Testconcentrations ranged from 25 ppm downward. The LD-50 values areexpressed below in Table II under the heading "Diabrotica" in terms ofppm of the test compound in the soil.

Black cutworm (Agrotis ipsilon):

Test compounds were dissolved in acetone and aliquots pippetted intosmall cups containing 10 grams of a soil mix. The compound was thenincorporated into the soil. A piece of lettuce was placed in each cupand five 3rd instar black cutworm larvae introduced. The cups werecapped and held for two days at constant temperature, then examined forlive larvae. Test concentrations ranged from 25 ppm downwards. The LD-50values are expressed below in Table II under the heading "BC" in termsof ppm of the test compound in the soil.

Acaricidal Evaluation Test

The two-spotted mite (2SM) [Tetranychus urticae (Koch)] was employed intests for miticides. The test procedure was as follows:

Pinto bean plants (Phaseolus sp.) approximately 10 cm tall, weretransplanted into sandy loam soil in small cups and thoroughly infestedwith two-spotted mites of mixed ages and sexes. Twenty-four hours laterthe infested plants were inverted and dipped for 2-3 seconds in 50--50acetone-water solutions of the test compounds. Treated plants were heldin the greenhouse, and 7 days later mortality was determined for bothadult mites and the nymphs hatching from eggs which were on the plantsat the time of treatment. Test concentrations ranged from 0.05%downward. The LD-50 values are expressed below in Table II under theheadings "2SM-A" (i.e., adults) and "2SM-E" (i.e. eggs) in terms ofpercent concentration of the test compound in the solution.

Systemic Evaluation Test

This test evaluates the root absorption and upward translocation of thecandidate systemic compound. The two-spotted mite (2SM) [Tetranychusurticae (Koch)] and the bean aphid (BA) [Aphis fabae (Scop.)] wereemployed in the test for systemic activity. Tests were conducted asfollows;

Two-Spotted Mite:

Test compounds were dissolved in acetone and aliquots diluted in 200 mlof water in glass bottles. Two pinto bean plants (Phaseolus sp.), withexpanded primary leaves, were supported in each bottle by cotton plugsso that their roots and stems were immersed in the treated water. Theplants were then infested with 75-100 two-spotted mites of various agesand sexes. One week later the mortality of the adult mites and nymphswas recorded. Test concentrations of the chemicals in the water rangedfrom 10 ppm downward. The LD-50 values are expressed in Table II underthe heading "2-SM (S)" in terms of ppm of the test compound in thesolution.

Black Bean Aphid [Aphis fabae (Scop.)]

Nasturtium plants (Tropaeolum sp.), approximately 5 cm tall, weretransplanted into 400 grams of sandy loam soil in one pint containers.Test chemicals were dissolved in acetone and aliquots diluted in 50-60ml of water. The treated water was poured onto the surface of the soiland allowed to thoroughly soak in. The treated plants were infested with25-50 black bean aphids of mixed ages and held in the greenhouse.Mortality was recorded after three days. Test concentrations ranged from10 ppm down to that at which 50% mortality occurs. The LD-50 values areexpressed in Table II under the heading "BA(S)" in terms of ppm of thetest compound in the soil.

Soil Bioassay on Root Knot Nematode (Meloidogyne incognita)

A nematode colony was maintained on tomato plant roots (Lycopersiconsp.) grown in clay pots. Aliquots of nematode-infested soil were removedfrom these pots and placed in small cups. Test compounds were thenincorporated into the soil. Four squash seeds were planted in each cupand watered as required.

Twenty-one days later the squash plants were removed and washed and theroots examined for the presence or absence of root nodules. Testconcentrations ranged from 25 ppm (final concentration in the soil)downward. The LD50 values are expressed in Table II under the heading"RKN" in terms of ppm of the test compound in the soil.

                                      TABLE II                                    __________________________________________________________________________    (LD.sub.50)                                                                                                                             Dia-                                                                          brotica,            Cmpd.                                                                             HF, μg                                                                             BA       2-SM        TBW, %  BAW,                                                                              CL,  BC, RKN,                                                                              ppm                 No. C   F*  C, %                                                                              S, ppm                                                                             A, %                                                                              S, ppm                                                                            E, %                                                                              C   E   %   %    ppm ppm (soil)              __________________________________________________________________________    1     40                                                                               <50                                                                              0.05                                                                              >10  0.03                                                                              >10 0.05                                                                              0.05                                                                              0.1 0.07                                                                              0.03 --  --  3                   2     76                                                                                76                                                                              0.03                                                                              >10  0.03                                                                              >10 0.05                                                                              0.04                                                                              0.05                                                                              0.01                                                                              0.008                                                                               8    4 0.3                 3     29                                                                               <50                                                                              0.03                                                                              6    0.01                                                                              >10 0.003                                                                             >0.05                                                                             0.05                                                                              0.01                                                                              0.009                                                                              3.5 7.5 2                   4     35                                                                               <50                                                                              0.002                                                                             >10  0.05                                                                                2 0.03                                                                              0.03                                                                              0.005                                                                             0.03                                                                              0.008                                                                               5    4 0.75                5   >100                                                                                78                                                                              0.03                                                                              6    0.03                                                                              >10 0.03                                                                              >0.05                                                                             >0.05                                                                             >0.05                                                                             0.03 10   17 0.3                 6   >100                                                                              --  0.01                                                                              2    >0.05                                                                             >10 >0.05                                                                             0.03                                                                              0.008                                                                             0.03                                                                              0.01  9  >25 0.75                7     23                                                                                91                                                                              0.006                                                                             6    0.05                                                                                3 0.05                                                                              0.03                                                                              0.03                                                                              0.1 0.006                                                                               7  7.5 0.75                8   >100                                                                              --  0.01                                                                              3    0.05                                                                              >10 0.05                                                                              0.03                                                                              0.05                                                                              0.1 0.008                                                                              17  >25 0.4                 9   >100                                                                              >100                                                                              >0.05                                                                             >10  >0.05                                                                             >10 >0.05                                                                             0.009                                                                             0.03                                                                              0.05                                                                              0.0025                                                                             >25 >25 4                   10  >100                                                                              >100                                                                              0.01                                                                              6    0.01                                                                                6 0.05                                                                              0.1 >0.1                                                                              0.035                                                                             0.007                                                                              17   17 1                   11    19                                                                                77                                                                              0.006                                                                             >10  0.05                                                                                3 0.05                                                                              0.03                                                                              0.02                                                                              0.01                                                                              0.008                                                                              15   17 0.75                12  >100                                                                              >100                                                                              0.01                                                                              >10  >0.05                                                                             >10 >0.05                                                                             >0.1                                                                              0.07                                                                              0.035                                                                             0.008                                                                              25  >25 0.75                __________________________________________________________________________     Key:                                                                          C = Contact Test                                                              F = Fumigant Test                                                             S = Systemic Test                                                             E = Test on Eggs                                                              A = Test on adults                                                            *Per 285 ml volume container                                             

Soil Residual Control of Diabrotica

Test compounds showing LD₅₀ values of 2 ppm or less in the Diabroticaevaluation procedures were submitted for evaluation of residual controlof this insect. Compounds 2 through 8 and 10, 11 and 12 were evaluatedby the following procedure.

Test compounds were thoroughly incorporated into 900 g of finelyscreened, dry, sandy loam. To this was added 100 cc of water, for afinal moisture level of 10% and a final chemical concentration of 2 ppm.Treated soils were maintained in tightly sealed containers at atemperature of 78° F. (25.5° C.). Starting at 2 weeks after treatment,and at weekly intervals thereafter, 10 g samples were taken from thestorage containers and placed in small cups. An indentation was made inthe soil surface and approximately 50 Diabrotica eggs were added,covered with soil, and the cups were covered. A piece of Romaine lettucewas added to each cup four days later when the eggs hatched. The cupswere then examined for live larvae one week later and thereafter atweekly intervals.

Table III indicates the number of weeks after the initial treatment thatthe test compound provided 100% control of the Diabrotica larvae.

                  TABLE III                                                       ______________________________________                                        Compound No.    Weeks                                                         ______________________________________                                        2               8                                                             3               2                                                             4               2                                                             5               8                                                             6               3                                                             7               2                                                             8               5                                                             10              2                                                             11              <2                                                            12              3                                                             ______________________________________                                    

In practice, a pure compound can be used as an insecticide. However, ingeneral, the compounds are first formulated with one or more inert (i.e.non-chemically reactive, plant compatible or herbicidally inert)carriers or diluents suitable for insecticidal use, before beingapplied.

The compositions or formulations, including a compound as describedherein, may take any one of a number of solid or liquid forms. Examplesof solid forms are dusts, granules, tablets, powders and the like.Examples of liquid forms are emulsions, solutions, suspensions,flowables, emulsifiable concentrates and pastes. Such compositions maycontain, in addition to the active compound or compounds, variouscarriers or diluents; surface-active agents (wetting agents, dispersingagents and/or emulsifying agents); solvents (water, or organic solventssuch as aromatic solvents or chlorinated aliphatic solvents); adhesives;thickeners; binders; anti-foaming agents; and other substances asmentioned herein. Solid carriers or diluents included in suchcompositions or formulations may include, for example, ground naturalminerals such as kaolins, alumina, calcined diatomaceous earth, calciumcarbonate, silica, kieselguhr, clays, etc.; ground synthetic mineralssuch as various silicates and alumino-silicates and ground vegetableproducts such as bark, cornmeal, sawdust, cellulose powder and the like.Compositions containing sorptive clays will usually also contain astabilizer, such as a glycol, to prevent or minimize degradation of theactive ingredient.

To manufacture solid compositions, the active substances are mixed withsolid carriers or diluents such as those mentioned above and the mixtureis ground to the appropriate size. Granules can be manufactured bydissolving an active compound in an organic solvent and applying themixture, for example, by atomization, onto an absorptive granulatedinert material, such as silica. Adhesives may be utilized to assist inthe incorporation of the compound onto the solid particles.

Wettable powders and pastes are obtained by mixing and grinding anactive compound with one or more dispersing agents and/or solid carriersor diluents. Also included may be wetting agents and/or dispersingagents, for example, lignins, methyl cellulose, naphthalenesulfonic acidderivatives, fatty alcohol sulfates and various types of alkali andalkaline earth metal salts of fatty acids.

Emulsifiable concentrates are generally obtained by dissolving theactive compound in an organic solvent, for example, butanol,cyclohexanone, xylenes, or higher boiling aromatic hydrocarbons. Toobtain suspensions or emulsions in water, wetting agents may also beadded.

Flowables are prepared by mixing an active compound with one or moredispersing agents and/or solid additives, and a liquid (which may bewater or an organic solvent) in which the active compound is relativelyinsoluble, and grinding the mixture.

Both liquid and solid compositions may be in microcapsule orencapsulated form, to permit release of the enclosed active compound ata controlled rate over a period of time. Liquid compositions of thistype contain encapsulated droplets of approximately 1-50 microns indiameter, including the active compound and optionally a solvent. Theencapsulating material is an inert porous membrane of a polymericmaterial.

Solid encapsulated compositions generally take the form of granules, inwhich the liquid containing the active component is trapped in the poresof the granular support by a porous polymeric membrane through which theactive ingredient may migrate at a controlled rate, or which membranebreaks down at a controlled rate to permit escape of the activeingredient.

Typical encapsulating materials include natural and synthetic rubbers,cellulosic materials, styrene-butadiene copolymers, polyacrylonitriles,polyacrylates, polyamides, polysisocyanates, polyurethanes, mixedcopolymers of the foregoing and starch xanthates.

It is possible to use highly concentrated liquid compositions containingup to about 95% by weight of the active compound, or even the 100%active compound alone, when applying the compound in the form of afinely divided liquid by use of various atomizing equipment, for exampleby airplane spraying techniques. For other purposes, however, thevarious types of compositions which can be utilized for these compoundswill contain varying amounts of the compound according to the type ofcomposition and the intended use.

In general, insecticidal compositions may contain from 5 to 95% of theactive compound, more preferably from 10 to 85%. Some typicalcompositions will contain an active compound as follows: wettablepowders: 25 to 80% active compound; oil suspensions, emulsions,solutions, flowables, and emulsifiable concentrates: 5 to 85% activecompound; aqueous suspensions: 20 to 50% active compound; dusts andpowders: 5 to 20% active compound; granules and pellets: 5 to 20% activecompound.

In addition to the active compound and the various agents utilized inpreparing compositions and formulations mentioned, such compositions mayalso contain one or more other active compounds of the type mentionedherein as well as other active pesticidal agents, such as herbicides,fungicides, insecticides, acaricides, nematocides, bactericides, andplant growth regulators. Such compounds may also contain soildisinfectants or fumigants and may further contain fertilizers, thusmaking it possible to provide multi-purpose compositions containing oneor more of the active compounds described herein as well as, optionally,other pesticides and also fertilizers, all intended and formulated foruse at the same locus.

Control of insect pests is accomplished by applying a compositioncontaining an insecticidally effective amount of an active compound asdescribed herein to the insect, to a locus at which insecticidal controlis desired, or to food sources (including seeds) on which the insectsfeed. For use in the last mentioned manner it is preferable to utilize acompound which is not volatile. Thus, control may be achieved by directapplication of the active compounds to the insects and indirectly byapplication of the compounds to a locus to be protected (such as croplands, grass ranges and forests), to a source of food for insects or toother insect habitats (for example, breeding or swarming areas). Therates of application of the active compound, and the concentrationapplied, will vary according to whether the compound or composition isbeing directly applied to the insect or indirectly, to a locus, food orhabitat. In the latter case the rate of the application, depending onthe nature of the insect or insects to be controlled, and the plantenvironment, will generally vary from about 0.01 to about 100 pounds peracre (about 0.011 to about 111 kg/ha).

It should be noted that the active compound need not be insecticidallyactive per se to effect insect control. The purpose of this inventionare fully served if such compounds are rendered active by externalinfluences, such as light or heat, or by some physiological action whichoccurs when the compound is ingested into the body of the insect.

Compositions containing one or more of the active compounds described,in an insecticidally effective amount, may be applied to the plant,locus or insect habitat in any conventional manner.

When used in connection with crop or other plant protection, applicationmay be made in a preventive (i.e. before infestation) or eradicativemanner (i.e., after infestation). Thus, powders and various liquidcompositions containing the active compound can be applied by the use ofpower dusters, boom and hand sprayers and spray dusters, or applied fromairplanes as dusts or sprays. When applied in the latter method they maybe effective in very low dosages.

Compositions including active compounds may also be applied by additionto irrigation waters supplied to the field to be treated. This method ofapplication permits penetration of the compounds into the soil as thewater is absorbed therein.

Compositions including active compounds may additionally be used toprotect plant seeds from being attacked by soil-borne insect pests afterplanting and during germination, by applying the composition to theseeds as a seed dressing. This is performed generally by mixing theseeds with an active composition in either liquid or solid form(preferably liquid) in a suitable mixing apparatus. Liquid compositionsfor this purpose may contain an adhesive or sticking agent, such asmethyl cellulose, ethyl cellulose, etc., to assist the composition inadhering to the seed. If a solid composition is utilized for thispurpose, an adhesive agent may be sprayed on the seeds during or aftermixing.

For use as a soil insecticide, the active compound, or compositionscontaining it, may be mixed with the soil in any conventional manner,before, during or after planting of the plant seeds. Liquid compositionsmay be applied by spraying onto the surface or by incorporation inirrigation or sprayed water. Solid or liquid compositions containing anactive compound may be incorporated into the soil prior to or duringplanting by discing, plowing or other mixing operations, in order tolocate the active ingredient below the surface of the soil so as to bemost effective in controlling undesirable larvae.

Some examples of compositions containing the active compounds of thisinvention are:

    ______________________________________                                        Component               Weight %                                              ______________________________________                                        Composition A: Granular Solid                                                 Compound 2              10                                                    attapulgite clay granules                                                                             85                                                    triethylene glycol       5                                                    Total                    100%                                                 Composition B: Wettable Powder                                                Compound 4              80                                                    wetting agent (sodium dialkyl-                                                                         1                                                    naphthalene sulfonate)                                                        dispersing agent (sodium                                                                               4                                                    lignosulfonate)                                                               diluent (aluminum magnesium                                                                           15                                                    silicate)                                                                     Total                    100%                                                 Composition C: Dilute Solution                                                Compound 5               5                                                    solvent (xylene)        95                                                    Total                    100%                                                 Composition D: Emulsifiable Concentrate                                       Compound 6              50                                                    Emulsifier (blend of metal                                                                            10                                                    sulfonates and polyoxy-                                                       ethylene ethers)                                                              solvent (xylene)        40                                                    Total                    100%                                                 Composition E: Concentrated Solution                                          Compound 8              90                                                    solvent (xylene)        10                                                    Total                    100%                                                 ______________________________________                                    

What is claimed is:
 1. A method of controlling insects applying to saidinsects or to a locus at which control is desired an insecticidallyeffective amount of a compound having the formula ##STR6## in which R₁is methyl or ethyl; R₂ is C₁ -C₆ alkyl; R₃ is hydrogen, halogen ormethyl; and R₄ is hydrogen, methyl or phenyl; or R₃ and R₄ takentogether form a tetramethylene chain; provided that R₃ and R₄ are notboth hydrogen.
 2. A method according to claim 1 in which the compound isapplied to soil to control insects which may be present therein.
 3. Amethod according to claim 1 in which R₂ is C₃ -C₆ alkyl.
 4. A methodaccording to claim 1 in which R₃ is methyl.
 5. A method according toclaim 4 in which R₄ is hydrogen.
 6. A method for controlling root knotnematodes comprising applying to said nematodes or to a locus whichcontrol is desired a nematicidally effective amount of a compound havingthe formula ##STR7## in which R₁ is methyl or ethyl; R₂ is C₁ -C₆ alkyl;R₃ is hydrogen, halogen or methyl; and R₄ is hydrogen, methyl or phenyl;or R₃ and R₄ taken together form a tetramethylene chain; provided thatR₃ and R₄ are not both hydrogen.
 7. An insecticidal or nematicidalcomposition of matter comprising:(a) an insecticidally or nematicidallyeffective amount of a compound having the formula ##STR8## in which R₁is methyl or ethyl; R₂ is C₁ -C₆ alkyl; R₃ is hydrogen, halogen ormethyl; and R₄ is hydrogen, methyl or phenyl; or R₃ and R₄ takentogether form a tetramethylene chain; provided that R₃ and R₄ are notboth hydrogen; and (b) an insecticidally or nematicidally suitablediluent or carrier.
 8. A compound having the formula ##STR9## in whichR₁ is methyl or ethyl; R₂ is C₁ -C₆ alkyl; R₃ is hydrogen, halogen ormethyl; and R₄ is hydrogen, methyl or phenyl; or R₃ and R₄ takentogether form a tetramethylene chain; provided that R₃ and R₄ are notboth hydrogen.
 9. A compound according to claim 8 in which R₂ is C₃ -C₆alkyl.
 10. A compound according to claim 8 in which R₃ is methyl.
 11. Acompound according to claim 10 in which R₄ is hydrogen.
 12. A compoundaccording to claim 8 in which R₁ is ethyl, R₂ is tert-butyl, R₃ ismethyl, and R₄ is hydrogen.
 13. A compound according to claim 8 in whichR₁ is methyl, R₂ is sec-butyl, R₃ is methyl, and R₄ is hydrogen.
 14. Acompound according to claim 8 in which R₁ is ethyl, R₂ is tert-butyl, R₃is hydrogen and R₄ is methyl.
 15. A compound according to claim 8 inwhich R₁ is methyl, R₂ is sec-butyl, R₃ is hydrogen, and R₄ is methyl.16. A compound according to claim 8 in which R₁ is methyl, R₂ istert-butyl, R₃ is methyl, and R₄ is hydrogen.
 17. A compound accordingto claim 8 in which R₁ is methyl, R₂ is methyl, R₃ is methyl, and R₄ ishydrogen.
 18. A compound according to claim 8 in which R₁ is methyl, R₂is n-propyl, R₃ is hydrogen, and R₄ is methyl.
 19. A compound accordingto claim 8 in which R₁ is methyl, R₂ is n-propyl, R₃ is methyl, and R₄is hydrogen.
 20. A compound according to claim 8 in which R₁ is methyl,R₂ is tert-butyl, R₃ is hydrogen, and R₄ is phenyl.
 21. A compoundaccording to claim 8 in which R₁ is methyl, R₂ is tert-butyl, R₃ ismethyl, and R₄ is methyl.
 22. A compound according to claim 8 in whichR₁ is methyl, R₂ is sec-butyl, R₃ is methyl, and R₄ is methyl.
 23. Acompound according to claim 8 in which R₁ is methyl, R₂ is tert-butyland R₃ and R₄ taken together form a tetramethylene chain.